Serrated Isolation Plug Gripper for Hard Pipe Sealing

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Solution Overview

Problem

Existing test and isolation plugs face challenges in gripping and sealing pipes made of high-hardness materials, such as stainless steel and nickel-based alloys, as they require excessive force and often deform the pipe walls, leading to incomplete sealing and increased repair needs.

Innovation Solution

The introduction of serrated gripper segments with a unique profile featuring alternating rows of teeth and gaps, which reduce the force required for engagement and provide enhanced holding capacity, flexibility, and reduced material deformation, allowing for effective sealing in pipes with higher hardness levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional smooth gripper segments are used to seal pipes, then the plug can be manufactured with simple structure, but excessive force is required and pipe wall deformation occurs leading to incomplete sealing

Engineering Contradiction:
Improvesealing effectivenessVSAvoidengagement force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The gripper segment is divided into multiple teeth elements arranged in alternating rows, where each tooth acts as an independent gripping element. This segmentation allows the force to be distributed across multiple contact points rather than concentrated on a smooth surface, enabling effective engagement with high-hardness pipe materials at reduced overall force levels.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The gripper segment features localized gripping zones at the teeth contact points rather than uniform contact across the entire segment surface. The teeth are positioned to create specific high-stress contact areas that concentrate gripping force precisely where needed to bite into the pipe wall, while gaps between teeth allow selective engagement based on local pipe geometry and hardness variations.

Inventive Principle:
Principle #3Local quality

2Reliability

If conventional smooth gripper segments are used, then manufacturing is simpler, but pipe wall deformation occurs leading to incomplete sealing

Engineering Contradiction:
Improvesealing effectivenessVSAvoidgripper segment manufacturing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The gripper segment is divided into multiple teeth elements arranged in alternating rows, where each tooth acts as an independent gripping element. This segmentation allows the force to be distributed across multiple contact points rather than concentrated on a smooth surface, enabling effective engagement with high-hardness pipe materials at reduced overall force levels.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The gripper segment features localized gripping zones at the teeth contact points rather than uniform contact across the entire segment surface. The teeth are positioned to create specific high-stress contact areas that concentrate gripping force precisely where needed to bite into the pipe wall, while gaps between teeth allow selective engagement based on local pipe geometry and hardness variations.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If conventional smooth gripper segments are used, then the structure is simpler, but the plug cannot effectively grip high-hardness materials like stainless steel and nickel-based alloys

Engineering Contradiction:
Improvecompatibility with high-hardness materialsVSAvoidgripper segment structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The gripper segment is divided into multiple teeth elements arranged in alternating rows, where each tooth acts as an independent gripping element. This segmentation allows the force to be distributed across multiple contact points rather than concentrated on a smooth surface, enabling effective engagement with high-hardness pipe materials at reduced overall force levels.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The alternating rows of teeth are positioned asymmetrically to create differential engagement patterns with the pipe wall. This asymmetric arrangement allows the gripper to adapt to variations in pipe hardness and geometry, with certain teeth engaging more deeply into softer regions while others contact harder surfaces, providing versatile compatibility across different material types.

Inventive Principle:
Principle #4Asymmetry

4Adaptability or versatility

If conventional smooth gripper segments are used, then the design is simpler, but the plug lacks flexibility in adapting to different pipe geometries

Engineering Contradiction:
ImproveflexibilityVSAvoidgripper segment structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The gripper segment is divided into multiple teeth elements arranged in alternating rows, where each tooth acts as an independent gripping element. This segmentation allows the force to be distributed across multiple contact points rather than concentrated on a smooth surface, enabling effective engagement with high-hardness pipe materials at reduced overall force levels.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The alternating teeth configuration creates a dynamic engagement pattern where individual teeth can independently adjust their contact depth and angle based on local pipe geometry. This dynamic adaptability allows the gripper segment to conform to variations in pipe diameter, ovality, and surface irregularities, providing flexibility across different pipe types without requiring multiple specialized components.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The serrated gripper segments enable successful high-pressure sealing in pipes with materials like stainless steel and nickel-based alloys, increasing the safety factor and service life of the plugs while minimizing damage and the need for post-test repairs.

Implementation Method 1

The gripping function is required to enable the plug to resist movement, sliding, failure, blow-out and/or leakage during testing at working pressures

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

serrated gripper segments with a unique profile featuring alternating rows of teeth and gaps, which reduce the force required for engagement and provide enhanced holding capacity

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP3158253B1Test and isolation plug with gripper
Publication Date: 2021.02.24 EST GROUP
  • EP3158253B1 patent drawingFigure 1
  • EP3158253B1 patent drawingFigure 2~4
  • EP3158253B1 patent drawingFigure 3

AI summary

A gripper for a test or isolation plug (40) is provided. The gripper includes at least one gripper segment (54) having a pipe or tube confronting surface (70) with a plurality of separate rows of gripper teeth (72) longitudinally-spaced apart on the surface (70). Each of the separate rows of gripper teeth (72) comprising an alternating array of individual tips (80) and gaps (78) such that each row is serrated along its length.